When processing color photographic light sensitive materials typified by a silver halide photographic light sensitive material comprising a silver iodobromide as the silver halide thereof, a processing bath containing formaldehyde has been used in the final processing step following a washing bath.
It is known that formaldehyde used in the above-mentioned processing bath has an effect on the physical properties of color photographic-light sensitive materials and, particularly, in preventing scratching produced on the color photographic light sensitive material surface and preventing contrast variation produced by gradually hardening of the photographic light sensitive material during aging. It is also known that formaldehyde has an effect on preventing dye-image stability deterioration produced by unreacted coupler remaining in the color photographic light sensitive material.
However, when formaldehyde is added to a processing bath for the purpose of stabilizing a dye-image for example, not only can formaldehyde deteriorate the dye image stabilizing effect, but it can also accelerate sulfuration, because formaldehyde adheres to the light sensitive material and forms an adduct with sulfite ions carried over from the precedent bath (containing a processing solution having a fixing function).
For solving the above-mentioned problems, it has been proposed to use alkanol amine as described in U.S. Pat. No. 4,786,583. However, when making use of the alkanol amine, unexposed portions are affected by yellow stains and the sulfuration prevention effect cannot be said to be satisfactory.
In additional to the problems of product when using formaldehyde, as discussed above, there are serious environmental concerns. In the U.S.A., CIIT (standing for Chemical Industry Institute of Toxicity) has reported that rats developed nasal cavity cancer when exposed to 15 ppm each of formaldehyde. Also, NIOSH (standing for National Institute of Safety and Health) and ACGIH (standing for Authority Conference of Governmental Industrial Health) each warn that there is a carcinogenic possibility. Further, in Europe, formaldehyde is subject to strict regulations and, particularly in Germany, formaldehyde was regulated to be not more than 0.1 ppm in housing 10 years ago.
In Japan, legal regulations applying formaldehyde have been put into force; including laws concerning violent poisons and dangerous drugs legislated because of skin irritation, concerning poisonings from organic solvents, regulations concerning household articles, regulations concerning fibers and plywood, and formaldehyde regulations concerning underwear and baby clothing which has newly put in force since 1975 by the Ministry of Public Welfare. As mentioned above, it has been eagerly desired to provide a technology capable of reducing the use of formaldehyde.
As for the techniques for substantially eliminating or reducing a formaldehyde content of a stabilizer, the means for achieving the above-mentioned object include the use of hexahydrotriazine type compounds disclosed in Japanese Patent Publication Open to Public Inspection (hereinafter referred to as JP OPI Publication) Nos. 62-27742/1987 and 61-151538/1986 and the use of N-methylol type compounds disclosed in U.S. Pat. No. 4,859,574.
The above-mentioned hexahydrotriazine type compounds may be able to prevent dye from color-fading at high temperature and high humidity even if formaldehyde is substantially eliminated. However, there still remains a problem unsolved that the compounds do not achieve an improved effect when used at a lower humidity such as at a relative humidity of not higher than 20%. These compounds have the additional problem of preservation stability of stabilizer, that is, the stabilizer is liable to be sulfurized in particular, though the problem is not as great as in the case of formaldehyde. When a process is carried out for a long time, when processing quantity is small or when a small amount of replenishment is supplied, it was found that the above-mentioned preservation stability becomes problematic.
When the above-mentioned N-methylol type compounds are used as the compounds to substitute for formaldehyde, they are not satisfactory in dye-fading prevention effect, back side staining prevention effect or stabilizer preservation. When trying to prevent dye from color-fading, there is a problem that the preservability of a stabilizer is seriously deteriorated.
The methods for making use of a hexamethylene tetramine type compound in a stabilizer have also been disclosed. However, these methods have a defect that the dye-fading prevention effect thereof is not satisfactory under low humidity conditions, similarly the foregoing hexahydrotriazine type compounds.
As a result of the various studies made by the present inventors, they have been able to discover that a specific aromatic aldehyde can be used to achieve the object of this invention. However, the use of aromatic aldehydes in photographic processing solutions is known. For example, salicylic aldehyde, furfural, 1-hydroxy-benzene-2,4-dialdehyde and so forth described in JP OPI Publication No. 49-83441/1974, French Patent No. 1,543,694 and so forth have been used.
However, the compounds described in the art fail to provide effects to meet the objects of this invention. Unexpectedly, the inventors hereof discovered that by introducing a particular substituent into the meta position of benzaldehyde, dye fading prevention at low humidity and yellow staining prevention can be attained. The known compounds, discussed above, have substituents, but these are in the ortho or para position thereof. Therefore, the effects of the purposes of the invention are not satisfactorily displayed. The art failed to show or suggest that the above-mentioned effects can be displayed when the specific substituent is introduced into the meta position thereof, as described above. In addition to the above, it was also discovered that scratch resistance can be improved as another effect when making use of a compound of the invention and, therefore, this invention could be achieved.
It is, therefore, an object of the invention to provide a processing solution for color photographic use; wherein, first, dye-fading can be prevented at low humidity even if formaldehyde is not substantially contained; second, the scratch resistance of light sensitive materials can be improved; third, solution preservability can be excellent and, particularly, a solution which is only slightly sulfurizable can be supplied; fourth, any yellow stains which may be produced in an unexposed portions, can be reduced; and fifth, the working environment safety can be improved; and to provide the processing method therefor.